Potential diagnostic role of urinary exosomal microRNAs in immunoglobulin A nephropathy: A case-control study

The most common type of primary glomerulonephritis is immunoglobulin A nephropathy (IgAN), which can eventually cause end-stage kidney disease among individuals. A kidney biopsy, which is invasive and has risks of mortality or morbidity, is currently the "gold standard" for diagnosis. Urinary exosomes contain abundant, well-preserved microRNAs (miRNAs), which are small, non-coding endogenous RNAs that may be used as non-invasive biomarkers. Studies on urinary exosomal miRNA profiles for the diagnosis of IgAN are rare.

To examine the profile of urinary exosomal miRNAs in Indian individuals diagnosed with IgAN.

Over a period of 4 years (2020-2024), fifty biopsy-confirmed IgAN patients, fifty healthy controls, and fifty disease controls (DC) were recruited. Urinary exosomes were first discovered and then utilized for miRNA extraction. The nCounter^® Human v3 miRNA Expression Assay, a digital multiplex technique that evaluates 798 unique miRNA barcodes, was used to further analyze the extracted miRNAs. After the least absolute shrinkage and selection operator feature selection identified candidate miRNAs, logistic regression and the CombiROC algorithm were used.

The average age of patients diagnosed with IgAN was 36.32 years, with a standard deviation of 3.07 years. The average proteinuria was 2.69 ± 0.64 g/day, and the average creatinine level was 2.26 ± 0.318 mg/dL. Nine candidate miRNAs - hsa-miR-4532, hsa-miR-4488, hsa-miR-3158-3p, hsa-miR-151b, hsa-miR-3195, hsa-miR-1289, hsa-miR-20a-5p, hsa-miR-20b-5p, hsa-miR-32-5p, and hsa-miR-525-3p - successfully differentiate IgAN cases from both healthy and DC, exhibiting under the curve values of 0.7, 1, and 0.8 for healthy controls, DC, and IgAN cases, respectively. When compared to healthy and DC, a combination of just two miRNAs - hsa-miR-4532 and hsa-miR-548a-3p - was found to be sufficiently effective for detecting IgAN, with an area under the curve > 0.8.

Our investigation involving Indian participants revealed a marked alteration in the urinary exosomal miRNA patterns among individuals with IgAN compared to both healthy subjects and those with other kidney diseases, demonstrating the effectiveness of miRNAs in the non-invasive diagnosis of IgAN.